The National Emergency Management Agency (NEMA) of New Zealand tweeted that the eruption was "hazardous in the immediate vicinity of the volcano". NEMA has called on people to "act promptly" on upcoming safety advice from local authorities.
According to local media, a rescue operation is underway, with several rescue helicopters on the way to the island.
Netizens have shared webcam photos near the island as well as satellite imagery capturing the moment of the eruption.
Located in the Bay of Plenty - approximately 48 km from the east coast of the North Island of New Zealand - Whakaari, or White Island, is New Zealand's most active volcano.